Putting coat on, return work left in class (14)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

ELECT (return); then OP + L(eft) in RATING, class. This last a bit iffy imo; a rating can be a classification (eg credit rating) but making it an actual class seems a stretch to me. Not in Collins, except as an Americanism. Electroplating itself is a fascinating subject. Read here about such delights as the Haring-Blum cell, used to test throwing power ..